JPH0849703A - Electro-pneumatic converter - Google Patents

Abstract

PURPOSE: To provide an electropneumatic converter that is readily convertible from a valve positioner into a pressure transducer and vice versa. CONSTITUTION: An electropneumatic converter device 10 includes modular components, and a supporting housing structure enabling it to be readily convertible from a current-to-pressure positioner into a current-to-pressure transducer. A valve positioner includes a housing 12, a modular base 26 and a separable field terminal box. A self-contained cover is mounted to an enclosure with no additional mounting parts. A plastic pneumatic relay 48 is ultrasonically welded so that no metal mounting parts are used and the assembly time is shortened. Open channels are cut in the housing surface cooperating with a gasket to provide fluid passageways between the housing 12 and the modular base 26. Pressure gauges 50 are removably mounted on a modular unit. A supply biased pneumatic pressure relay has supply pressure channeled to a support port and to a support bias cavity through a capillary hole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electropneumatic converter device, and more particularly to a current-to-pressure converter / positioning device.

BACKGROUND OF THE INVENTION Electro-pneumatic converters, such as current to pressure converters, are widely used in pipeline systems as field devices mounted to control process fluids. As such, these devices are installed in potentially explosive environments. Such a device
For example, it receives a varying current input signal of 4 to 20 mA and provides a varying pressure output to the actuator of the fluid control valve. Because these devices can be used in potentially explosive environments, electrical and pneumatic components are isolated within the explosion protection portion of the transducer and positioner to provide the explosion protection device. However, the pressure gauge that is usually placed outside the equipment is excluded.

The electro-pneumatic converters currently in use operate in potentially explosive areas, so if equipment repair or normal maintenance is required, a power supply is needed to perform the work. Must be removed or the entire device removed from the danger area. Occasionally, for example, pneumatic elements need to be adjusted or removed and replaced. With current equipment,
If the explosion protection of the device is unsealed in order to access these pneumatic elements, a dangerous situation arises in which the sparks generated on the electrical elements ignite explosive gases. Thus, powering down the device to repair it or move it out of the hazardous area is time consuming, expensive and wasteful.

In addition, it is necessary to mount the pressure gauge to the outer portion of the device's explosion protection while keeping the electrical and pneumatic components in the transducer and positioner's explosion protection device.

However, at this time, the pressure gauge is exposed not only to the atmosphere but also to physical damage due to accidental spraying of the pressure gauge protruding slightly from the outer surface of the transducer / positioning device.

[0006] Therefore, it is desired to manufacture an electropneumatic converter which can be used in an environment where there is a danger of explosion and which can repair pneumatic components without stopping electricity or moving the entire apparatus out of the hazardous area. .

In addition, it is desirable to make an electropneumatic transducer that protects the pressure gauge from the atmosphere and from accidental physical damage.

The pressure transducers currently in use are:
It incorporates a pressure-current sensor that converts the pressure signal into a current signal when sending feedback to the instrument. Analog pressure transducers are also available with each digital pressure transducer. Also currently available are separate valve positioners that accept valve feedback, supplied from a mechanical connection with the valve stem. Both the analog valve positioner and the digital valve controller can be used individually.

[0009] Generally, the customer chooses the type of instrument required to fit the equipment he currently owns. For this reason, customers first seek to purchase an analog pressure transducer instrument to best fit the equipment they currently own. If the customer's equipment changes, or if the customer wants to change the equipment to operate digitally, the customer must purchase the necessary extra instruments. Also, when a customer first bought a pressure transducer instrument and wanted to change to a valve positioner structure, the appropriate data format for the changed device,
You have to buy a new valve positioner. Therefore, it is even more desirable to create an electropneumatic instrument that is convenient to use and that can be easily converted from a pressure transducer to a valve positioner and vice versa. In addition, the user
It is desirable to be able to easily convert from analog data handling to digital data handling and vice versa. Furthermore, it is desirable that the user of the instrument be able to accept and adapt any required communication data protocol.

In existing electropneumatic instruments, the instrument housing is typically made of cast metal. The casting must then be precision drilled to form the passages and interconnecting passages to allow the passage of fluids between the parts. Drilling intersecting holes in a casting requires time consuming and precise drilling operations and preparation of the housing for drilling. Current instruments also use many individual subassemblies that require storage and assembly time. For example, instrument covers typically require multiple pins, locks, and other multi-part fasteners to attach the cover to the instrument. This requires inventory of several parts and requires a great deal of assembly time to attach the cover to the instrument.

Pneumatic relays, widely used in positioners and transducers, are usually made of aluminum-based materials. Small screws are used to assemble the aluminum relay body parts while clamping the rubber diaphragm and O-ring for pressure sealing. Assembling these many subassemblies of current pneumatic relays is tedious and expensive in a manufacturing environment.

Therefore, the parts are eliminated, or at least
It is desirable to reduce the number of parts required for electropneumatic instruments.

SUMMARY OF THE INVENTION The present invention provides a variety of modular electropneumatic instruments that provide a platform for assembling a wide range of output devices. The output device is a digital pressure converter, a digital valve controller, an analog valve positioning device, an analog pressure converter, or the like. All of the above output devices obtained by the present invention have the following features: Modular structure with field termination compartments, electronics compartments, pneumatic compartments, all environmentally isolated from each other.

2. Explosion-proof, modular structure that can be maintained and repaired without interfering with electrical components.

3. A modular structure that allows user-selected variations with feedback and can be mounted to accommodate slide valve stem valves and rotary shaft valve actuators.

The principles of the present invention provide a modular electropneumatic device which can be easily converted from a pressure transducer to a valve positioner and vice versa. According to a preferred embodiment of the present invention, a convertible instrument comprises an enclosure with a housing defining a hollow interior, a module base containing electropneumatic components, the module base being removable and inserted into the housing. The housing portion is contained within the housing and is adapted to include an electrometer and a shaft for converting the meter into a valve positioner. The housing part communicates with the hollow interior, and the output of the electrometer is connected to the module-based electrical components via the housing part and the hollow interior of the housing.

The housing portion may be formed of an extended cylindrical boss that extends along the housing and has a pocket interior at one end that houses the electrometer. Inside the pocket
Crossing the hollow interior of the housing, a bush is screwed to the extended cylindrical boss to support the electrometer shaft.
When converting the valve positioning device using the electro-pneumatic instrument of the present invention into a pressure converter, the electrometer is removed from the housing, the electrometer output cable is removed from the main printed circuit board attached to the module base, and the main circuit board is removed. Alternatively, as is well known in the art, this can be easily accomplished by having the pressure transducer accept a suitable signal.

A preferred embodiment is an electrical terminal box mounted in the housing with a passage between the interior of the housing and the terminal box. The electrical terminal board is interchangeably attached to a terminal box with a cover that can be removed for access. The cable harness is connected to the electrical terminal board of the terminal box, extends through the passage and the hollow interior of the housing, and is connected to the main circuit board of the module base. The terminal board and cable mounting band are
Analog, digital, communication, data protocols,
It is interchangeable so that it can accept the corresponding formats and features.

According to another aspect of the invention, the housing comprises a housing mounting surface that is substantially flat, with channels and slots open to the surface. The module base comprises a module base mounting surface opposite the housing mounting surface. A gasket is provided intermediate the housing mounting surface and the module base mounting surface. The gasket covers the open channel so as to define a fluid passage in the housing and further comprises an aperture that communicates the housing fluid passage to the module base fluid passage. A significant advantage of this aspect of the invention is that it is not necessary to have precise holes in the housing or precise positioning of the cross holes to form the required fluid transfer passages.

According to another aspect of the present invention, while holding the cover in the closed state on the module base,
A cover with built-in mounting ears is provided that is configured for easy insertion of the ears into the module base so that it can be easily removed from the module base when open.

According to yet another aspect of the present invention, there is provided a pneumatic relay comprising plastic molded structural parts. These parts can be ultrasonically welded to clamp a pressure-sealable diaphragm, eliminating the need for machine screws. This minimizes the number of subassemblies and drastically reduces assembly costs for pneumatic relays by almost half.

Electro-pneumatic conversion in the form of a current-pressure converter / positioning device, comprising an enclosure containing a housing and a module base, of an electro-pneumatic component with compartments of the device forming separate compartments for each of the electrical and pneumatic components. There are also vessels. The dividing inner wall between opposite sides of the module base defines a separating compartment between the dividing inner wall and the first portion of the module base opposite the dividing inner wall in the first direction. If possible, this separate compartment should contain electrical components. The other separation compartment is the inner partition wall,
A second direction, which is opposite to the first direction, is limited so that the pneumatic component is preferably housed between the divided inner wall and the second portion of the module base facing each other, preferably separated from the electric component.

A detachable cover is preferably attached to the separation compartment containing the pneumatic components. Thereby, removal of the cover provides access to the pneumatic component isolation compartment for repairing pneumatic components while keeping the electrical components isolated. Thus, according to the invention, the explosion-proof electronic compartment is isolated and unobstructed, and all the explosion-proof elements are in their original condition while the pneumatic element of the device of the invention is being repaired. Therefore, it is not necessary to turn off the power while working on the pneumatic components of the device of the invention.

A significant advantage of this aspect of the invention is that the pneumatic element can be adjusted, removed and replaced with the power supply connected without breaking the seal of the explosion proof part of the transducer / positioning device. is there. Another notable advantage is that maintenance diagnostics such as strokes of the pneumatic element to fully open and close to perform maintenance diagnostics on the device are obtained. The pneumatic element can be adjusted during maintenance or fault finding to change the zero pneumatic pressure. Also, according to the present invention, access to a supply pressure primary restriction that is clogged and requires cleaning is easily obtained.

According to another aspect of the invention, an electropneumatic converter comprises an enclosure having a housing defining a hollow interior and a module base removably insertable within the hollow interior of the housing so as to be surrounded by the enclosure. There is. The electrical and pneumatic components of the transducer are mounted on a module base with one or more pressure gauges, which pressure gauges are arranged in an enclosure,
As a result, it is protected from environmental and physical damage. Since the gauge mounted in the pneumatic compartment is always placed in an atmosphere that is being purged by the feed pressure medium, it will be protected from the corrosive atmosphere not found in devices with externally mounted pressure gauges.
The pressure gauge is preferably threadedly attached to the module base for ease of repair and replacement.

According to yet another aspect of the invention, the module base comprises a split inner wall. A first means is provided for mounting the electrical component on one side of the split interior wall. A second means is provided for mounting a pneumatic component, such as a pressure gauge, on the opposite side of the internal dividing wall. Thus, because the module base is insertably mounted within the housing, the separation compartment is limited to separate the electrical components from the pneumatic components.

According to yet another aspect of the present invention, an improved pneumatic relay for a fluid actuator control valve is provided. The supply pressure is transferred to the supply bias cavity through the capillary hole to maintain a substantially constant supply pressure for the relay. The pressure transition in response to load changes is isolated from the feed bias cavity by the capillary hole.

[0028]

EXAMPLES The features of the present invention believed to be novel are as follows.
Further details are set forth in the appended claims. The invention will be best understood by reference to the following description in conjunction with the accompanying drawings. In the drawings, like reference numbers refer to like elements in the several views. 1 is a front view depicting an electric current pressure transducer having an enclosure with a housing and a removable module base in accordance with the present invention.

FIG. 2 is a sectional view of the current-pressure converter shown in FIG. 1 taken along section line 2-2.

FIG. 3 is a sectional view of the current-pressure converter shown in FIG. 1 taken along the section line 3-3 of the module. Some parts have been removed for clarity.

FIG. 4 is a sectional view taken along the section line 4-4 of the current-pressure converter shown in FIG. Some parts have been removed for clarity.

FIG. 5 is a partial sectional view taken along the section line 4A-4A of the current-pressure converter shown in FIG.

FIG. 6 is a partial sectional view of the current-pressure converter shown in FIG. 1 taken along section line 5-5. Some parts have been removed for clarity.

FIG. 7 is a front view showing an interconnection board for connecting electrical terminals.

FIG. 8 is a front view showing the inside of the housing in which the interconnection board is mounted so that it can float.

FIG. 9 is a cross-sectional schematic view of shoulder screws for mounting the interconnection board in a floating condition.

FIG. 10 is a supply bias pneumatic relay.

FIG. 11 is a perspective view of the preferred embodiment of the invention, illustrating a modular valve positioner that can be easily retrofitted into a pressure transducer.

FIG. 12 is a sectional view of the preferred embodiment of the invention taken along section line 11-11 of the valve positioner shown in FIG.

FIGS. 13 and 14 are exploded perspective views of the modular valve positioning device of FIG. 11, and the two drawings show the same central reference axis in the directions indicated by the respective arrows.
They are connected and arranged.

FIG. 15 is a front view of the module base.
Some parts have been removed for clarity.

FIG. 16 is a sectional view taken along section line 14-14 of the module base shown in FIG.

FIG. 17 is a partial sectional view showing a pressure sensor for detecting the output pressure.

FIG. 18 is a front view of the instrument housing showing channels on the surface of the fluid passages.

FIG. 19 is a front view of the module base showing the surface of the module base facing the housing of FIG.

FIG. 20 is a schematic block diagram illustrating an electropneumatic converter that can be easily converted from a valve positioner to a pressure converter and vice versa.

The module and conversion aspects of the invention illustrated in FIGS. 1-10 will be described in the context of an embodiment comprising an amperometric pressure converter. It is to be understood that the teachings herein are equally applicable to other electropneumatic converter devices which solve the problems solved by the present invention. For example, although this description relates to current pressure transducers, such devices
It is well known in the art that current teachings can be readily converted to current pressure positioners according to the teachings herein.

The flexible module side and convertible side of the invention illustrated in FIGS. 11 to 20 will now be described in connection with a preferred embodiment comprising a current pressure positioning device.
This current-pressure positioning device can be retrofitted to a current-pressure transducer and vice versa more easily than the embodiment of FIGS. This description is to be understood as illustrating a preferred embodiment and is not intended to limit the scope of the invention or the claims. As such, the invention and claims contemplate a broad interpretation consistent with the teachings herein.

I Retrofittable Current Pressure Transducer Reference is now made to FIGS. Illustrated is an electric current pressure transducer 10 with an enclosure containing a housing 12 with a portion defining a hollow interior 14. The housing 12 contains a field terminal box portion 16 with field terminal strips 18 for making appropriate connections to electrical signal cables that receive current control signals from the power distribution control system, such as for process monitoring. . The end cap 20 is removable from the housing for proper cabling connection to the terminal 18.

The housing 12 also has an inlet 22 which receives a supply pressure from an air supply and an output pressure to a positioning device,
Alternatively, it has an outlet port 24 that can be directly connected to the valve actuator. In general, in response to a varying 4-20 mA current control signal, the current pressure transducer 10 provides a varying pressure output at the outlet 24.

The module base 26 (see FIG. 3) contains the electric components and the pneumatic components of the current-pressure converter 10. Generally, this is a current pressure converter such as an I / P nozzle block that converts a fluctuating current control signal input into a fluctuating nozzle pressure signal, a pressure relay that receives a fluctuating nozzle pressure signal and provides a fluctuating pressure output at outlet 24, Entrance port 22
From a pressure gauge connected to the to monitor the supply pressure, a second pressure gauge to monitor the pressure output at the outlet 24, an electronic device such as a pressure sensor or a printed circuit board, which is provided with a circuit for processing an electric signal as necessary. It is made up.

The module base 26 comprises a metal base 28 having a screw ring 30 and an O-ring 32 so that the module base 26 can be inserted into the housing 12 with a screw engagement. Referring to FIG. 2, the module base 26 is shown in a fully threaded mounting position when fully inserted into the housing 12.

The module base also includes a module wall 3
4 which mounts pressure components on one side and electrical components on the other side. Module base 26
In the facing wall 34, the mask plate 36 and the transparent cover plate 3
8 forms a pressure compartment 40 in the module base and is defined between the module wall 34 and the cover plate 38. Referring to FIG. 2, when the module base is insertably mounted in the housing, the electrical compartment 42 is defined as part of the housing interior 14, particularly between the module wall 34 and the housing side 44.

Referring to FIGS. 1-3, it can be seen that the pressure components are mounted on the module base on one side of the module wall 34 and the electrical components are mounted on the other side of the wall 34. For example, I / P nozzle block-flapper 46, pneumatic relay 48, pressure gauges 50, 52.
Are all mounted on one side of the wall 34 of the pneumatic compartment 40. A printed circuit board 54 with electrical components and pressure sensor 56 is mounted on the other side of the module wall 34 so that it enters the electrical compartment 42 when the module base is inserted into the housing.

Thus, as can be seen in FIG. 2, the electronic components are isolated in a separate pressure compartment 42 and the pressure components are separated in the separate pressure compartment 4 opposite the module wall 34.
Isolated to 0. All electropneumatic components, including the pressure gauge, are held within the instrument enclosure. Of course,
It is understood that a suitable explosion protection device is inserted into the orifice passing through the wall 34 which interconnects the compartments 40 and 42. For example, referring to FIG. 3, aperture 58 through wall 34 includes pressure gauge 52 and pressure sensor 56.
Interconnect with. A commercially available material known as fire arrester 60 is inserted into aperture 58. The fire arrestor 60 comprises a perforated metal plug that allows pressure to pass but reduces the flame temperature of the aperture 58 to prevent ignition of the hazardous environment.

The threaded ring 30 is free to rotate with respect to the metal base 28. The screw ring is fastened on one side between the metal bases 28 and the two struts 62 are fixed to the metal base 28 and comprise a protruding ledge 64 slightly spaced from the rim 66 of the screw ring 30. .

This causes the screw ring to rotate and threadably engage the screw housing portion 68 so that the metal base 28 can be securely attached and sealed with respect to the housing 12 through the O-ring 32.

According to one aspect of the present invention, the pressure component and the electrical component include a housing 1 for preventing an accidental spark of the electrical component that ignites the hazardous environment present in the pressure component.
2 and the module base 26 isolates it in an enclosure, but the pressure components do not power off or move the device 10 out of the hazardous area,
You can see that it can be repaired and maintained. Note that with respect to this aspect of the invention, removal of cover 38 and mask 36 from the enclosure allows access to the pressure components in pressure compartment 40 while leaving the electrical components of electrical compartment 42 isolated. .

Thus, the I / P nozzle block 46 is
It can be repaired without turning off the power. For example, the pneumatic element can be adjusted to zero air pressure during maintenance or failure detection because it has access to the zero adjustment nut 70 of the I / P nozzle block. There is also access to the cleanout wire 72, which can be used to remove air restrictions and to clean the orifices of air supply tubes that may become clogged. Similarly, without disconnecting power, the pressure gauge can be screwed out of the module and replaced if necessary. Repair of pneumatic relays can also be done with the electrical components of electrical compartment 42 completely isolated.

In accordance with another aspect of the present invention, the entire pressure gauge 50 and 52 is mounted within the enclosure formed by the housing 12 and the module base 26 and exposed to physical damage from the environment and acts outside the housing. It is noticeable that it should not be done. Moreover, the pressure gauge can be removed and the pressure section 40
Removable cover 38 to provide access to
It can be repaired by removing the mask 36.

FIG. 4 shows the inlet air supply at the inlet end 76 as I
The / P nozzle block 46 leads to the I / P nozzle block fluctuating pressure output to the pneumatic relay 48, showing the module wall 34 containing a vertical passage.

Referring now to FIG. 5, the module wall 3
4 and a passage connecting the inlet end 76 to the passage 77 and 79 from the main supply passage 81 to the I / P nozzle block 46,
It is shown. The fluctuating pressure output of nozzle block 46 is provided through passage 83 to interconnect passage 74 leading to pneumatic relay 48.

Referring to FIG. 3, the passage 81 connects to the lateral passage 85 at the inlet end 76 so as to ultimately communicate with the inlet port 22 which receives the air supply pressure when the modular is installed in the housing. I understand that.

Referring to FIG. 4, the aperture 78 is shown in the module wall, which allows electrical connection from the printed circuit board 54 through the module wall to the I / P nozzle block. There is. As previously mentioned, these apertures also incorporate suitable explosion-proof seals to prevent the sparks of electrical compartment 42 from igniting a hazardous potential environment through wall 34 to pressure compartment 40.

According to another aspect of the present invention, the combination of the connection between the housing terminal and the module terminal is a blind connection. That is, the module base 26
Is automatically performed when the is inserted into the housing 12.

The electronic components of the printed circuit board 54 are shown in FIG.
As will be apparent from the above, a module terminal strip 80 containing a module terminal 82 composed of a plurality of male terminal pins,
It is electrically connected. The printed circuit board 54 is mounted within a plastic cover 84, but preferably all devices within the plastic cover are epoxy molded. The cover 84 is then attached to the module wall 34 using suitable screws 86.
As shown in FIG. 6, the module terminal 82 includes a cover 84.
Projecting through and mating with female housing terminals 88 on housing terminal strip 90. 90 is attached to the housing interconnect plate 92.

Referring to FIGS. 7 and 8, the manner in which the housing interconnect plate is mounted in a floating condition for self-centering with the module terminal pins is shown.

The housing side wall 44 incorporates a pair of upstanding ribs 94, each with a threaded aperture for receiving a mounting screw 96. If possible, mounting screws 9
Reference numeral 6 denotes a shoulder screw, and it is preferable that the shoulder hits the rib so that the shoulder screw does not penetrate deeply into the threaded aperture of the rib.

Referring to the schematic diagram of FIG. 9, this structure is illustrated in more detail. The threaded apertures in the ribs 94 allow the screws 96 to engage until the shoulders 102 abut the ribs 94.
Accept the threaded portion 100 of the. As you can see in Figure 9,
The length of shoulder 102 is greater than the width of housing interconnect plate 92. As such, the housing interconnect plate can float vertically along the screw 96, between the screw head and the crest of the rib 94. If necessary, screw head 96
Dimensions can be determined for this purpose, and larger washers 106 may be utilized. Further, the diameter of the aperture 104 of the housing interconnect plate 92 is slightly larger than the diameter of the shoulder 102. This allows the interconnect plate to move slightly laterally with respect to the screw.
Thus, the housing interconnect plate is firmly supported by the screws 96 and ribs 4, but can float in a position between the screws and ribs so that the terminals of the housing insertably mount the module base 26 into the housing. Allows automatic alignment with the module terminals while in use. A longitudinal groove 108 is provided on the inner surface of the housing to guide the module terminals in the correct direction with respect to the housing terminals. The groove 108 fits with an index pin 110 fixed to the outer surface of the metal base 28. Thus, when the module base 26 is inserted into the housing, the module base rotates until the index pin 110 fits into the longitudinal groove 108 to properly position the module terminal 82 with the housing terminal 88. Thereafter, the female housing terminals 88 are aligned with the male module terminals 82, as the threaded ring 30 is floatingly attached to the housing interconnect plate 92 as it rotates to move the module base into the housing. The module base ultimately provides electrical interconnection with the housing interconnect plate. Figure 6
As shown in.

A flexible electrical cable 112 interconnects the housing interconnect plate 92 with a small printed circuit board 114, 114 being a series RFI filter 1.
16, the filter 116 is connected through the housing 12 to a suitable field terminal 18.

The housing interconnect base 92 also incorporates a suitable connector 118 for connection with the positioner, as the transducer can be readily converted to the positioner, as is well known in the art. For the converter, the plug 120 is attached to the side surface 44 of the housing and shuts off the electrical compartment 42. When the device is used as a positioning device, an electrometer is attached to the electrical compartment and is electrically connected to the connector 118, the electrometer shaft extending through the aperture and a suitable flame arrester attached to the plug.

Referring now to FIG. 10, a fluctuating output pressure is received at the outlet 124, which receives a fluctuating control pressure at the inlet 122 and which is connected to the air outlet 24 (see FIG. 1) of the housing 12 for communication with the valve actuator. Improved pneumatic relay 48
Is illustrated. The relay 48 also includes a supply pressure inlet 126 coupled with the inlet 22 (see FIG. 1) of the housing 12 for connecting with a source of air supply pressure. The relay 48 also includes an exhaust outlet 128.

The pneumatic relay 48 is provided with a supply bias portion for setting the start point of the pneumatic pressure input range at the inlet 122 for any supply pressure at the inlet 126. The starting point input pressure changes with changes in supply pressure, so the relay 48 can operate at different supply pressures without changing hardware such as bias springs. Referring to FIG. 10, it can be seen that the relay 48 includes an input signal diaphragm 130, an input supply port 132, and an exhaust port 134. The movement of diaphragm 130 corresponding to the fluctuating pressure input at inlet 122 is
Controls opening and closing of input supply and exhaust ports. The valve rod 136 has a supply valve plug 138 at one end and an exhaust valve plug 140 at the other end.

The valve spring 142 fixed to the plug 138 and the cap 144 normally fixes the plug 138 to the input supply port 132 as shown in FIG. This prevents the supply pressure from the inlet 126 from reaching the actuator outlet 124, otherwise the supply pressure will pass through the passages 146, 148, the open input supply port 132 and the passage 150. Through the actuator outlet 124
Leads to.

Input signal diaphragm 130 and valve rod 1
A drive connection between 36 is provided through three intermediate diaphragm mounting bodies, an upper body 152, an intermediate body 154, and a lower body 156. An upper feed bias diaphragm 158 is firmly supported between the bodies 152 and 154 and a lower feed bias diaphragm 16
0 is firmly supported between the middle block 154 and the lower block 156.

The supply bias cavity 162 is defined between the diaphragms 158 and 160, the intermediate block 154, and the outer casing 155. Casing 155
Capillary holes 164 therethrough connect the supply bias cavity to the supply pressure inlet 126 so that the supply bias cavity is under supply pressure almost always. This is why the supply pressure depends on the input supply port 13
In addition to being carried to the No. 2, it enters the supply bias cavity 162 via the capillary hole 164. Once the supply pressure is built up in cavity 162, it preferably remains unchanged during operation of relay 48. When the supply port 132 opens and closes, a temporary change in supply pressure occurs. The capillary hole is formed by the valve plug 138 in response to a change in load, which causes a change in pressure generated when the supply port 132 is opened or closed.
Isolates the supply bias cavity. Therefore, even if a slight pressure fluctuation occurs due to a change in the input signal, the valve portion is stable, so that the performance is improved.

FIG. 10 illustrates the relay 48 in the normal position. When an increasing fluctuating pressure is coupled to the inlet 122, the input signal diaphragm 130 flexes upwards, moving the bodies 156, 154, 152, the exhaust plug 140, the rod 136, the valve plug 138 upwards, and the supply port 13.
Remove 2. The exhaust port 134 remains closed. Therefore, the supply pressure is changed from the inlet 126 to the passages 146, 14
8. Connected to actuator outlet 124 through open feed input port 132, passage 150 and finally to valve actuator. It is noted that the lower supply bias diaphragm 160 has a larger diaphragm area than the upper supply bias diaphragm 158. Therefore, the relay is biased to form an output start point corresponding to the input signal based on the applied supply pressure.

II Retrofit Current Pressure Positioning Device Reference is made to FIGS. There is shown a preferred embodiment of an electropneumatic instrument which can be easily retrofitted from a current pressure positioner to a current pressure transducer and vice versa.
For example, the assembly views of FIGS. 11 and 12 illustrate a preferred electro-pneumatic conversion instrument 200 that is flexible and optimal for construction across currently available devices. In particular, the structure is modular for a few key instrument parts, with the following advantages:

(1) The instrument can be easily retrofitted from a valve positioner to a pressure transducer in a manner not possible with previous instruments.

(2) Multiple types of terminal boxes can be removably attached to the housing to accommodate multiple types of field connections and structures.

The electro-pneumatic conversion instrument 200 shown in the assembly drawings of FIGS. 11 and 12 comprises several basic enclosure components in modular form: housing 202, housing 202.
Is a type of valve positioning device that incorporates a field terminal box 204 that is separable and replaceably mounted, and a module base 206 that is also replaceably mounted on the housing 202. A removable cover 208 of the instrument enclosure is removably attached to the module base 206. Field terminal box 2
A terminal box cover 210 is attached to 04 to protect the contents from the environment.

The meter 200 is in the form of a valve positioner with a bushing 212 attached to an extended cylindrical boss 214 extending along the housing for mounting an electrometer 216. The extended cylindrical boss 214 is attached to the rear wall 2 of the housing.
A housing unit 2 extending along 18 and serving as a mold unit.
It is formed integrally with 02 (see FIG. 12). Boss 21
Reference numeral 4 is hollow and has an internal pocket 220 that intersects and communicates with the hollow interior 222 of the housing 202. As can be seen in the exploded view of FIG. 13, the positioning device 216 includes an electrometer 224 disposed in the inner pocket 220 and a printed circuit board extending through the inner pocket 220 into the housing hollow interior 222 and attached to the module base 206. It is inserted with the electrometer lead wire 226 and the connector plug 228 connected to 230. After that, the bush 212 slides on the electrometer shaft 232, screw-engages with the boss 220, and supports and attaches the electrometer shaft 232.
The electrometer 216 attached to the housing 202 is held.

With reference to the assembly view of FIG. 12 and the exploded view of FIG. 13, various components including electrometer 216 are shown attached to housing 202. In particular, the field terminal box 204 includes a male threaded end 233 on the housing 202 that mates with a corresponding female threaded portion 234 in a threaded manner. The terminal box 204 includes an interior 236 that extends from the interior 236 and extends at a right angle through the terminal 204 to a tubular passage 238 that extends to the other terminal end 240 that communicates with the hollow interior 232 of the housing 202.

The field terminal block 242 is attached to the printed wiring board 244, and 244 is attached to the cable mounting band 246 which ends in the connector plug 248. As can be seen in FIG. 13, the terminal block,
The printed wiring board, cable harness, and connector plug are all combined into one device. In particular, it is noted that the cable harness includes radio frequency interference (RFI) filter feedthrough 250 (see FIG. 12).

The salient feature of this structure is that it has a threaded RFI.
It is to reduce the manufacturing cost required to install the filter on the housing and solder the printed wiring board and terminal block to the RFI filter. In addition, the terminals shown in FIG. 13 can be replaced more easily and are more reliable in installation and operation. When installing the field terminal block 242 and associated cable attachment band, insert the connector plug 248 into the interior 236 and then:
Beyond the terminal end 240, it is inserted into the tubular passage 238 which continues to the hollow interior 222 of the housing 202. Plug 2
The 48 may then be connected to the main printed circuit board 230 of the module base 206. Terminal box 2
In 04, the printed wiring board 244 hits the O-ring 252, and the printed wiring board 244,
Move toward one end of tubular passageway 238 until it is held in place by screw 254. O-ring 252
Serves as a seal that seals the housing interior 222 and the main circuit board 230 from the environment. The terminal box cover 210 is threadedly attached to the terminal box and helps keep the electrical components unaffected by the environment.

The module base 206 has a partition wall 258.
It contains a main electrical compartment 256 isolated on one side, with pneumatic components on the other side of wall 258. Especially, I /
The current pressure transducer devices, such as the P nozzle block, flapper device 260, pneumatic relay 262, pressure gauges 264, 266 are all mounted on one side of the dividing wall 258 of the module base 206 and the other side of the wall 258. It is physically separated from the electrical components of Thus, the electrical components are retained in the explosion proof portion of the instrument enclosure. Also, all electropneumatic components, including pressure gauges, are retained within the instrument enclosure. Covers 208 are each provided with a transparent window for visual reading of gauges 264, 266.

The electrical connection from the main printed circuit board 230 to the I / P converter is through the appropriate aperture 270 to the I
Through the electrical contact 268 connected to the / P converter 260,
Supplied. The aperture 272 of the wall 258 is for allowing the supply pressure to communicate with the I / P converter 260. Aperture 274, as described in further detail below,
This is to connect the fluctuating pressure from the / P converter to the output of the meter.

FIG. 18 is a front view of the housing surface showing the supply pressure leading to the input port 276 and the passage 278 connecting the supply pressure to the open channel 280 in the housing surface 282. Surface 282 is instrument output port 2
There is also an additional group of open channels 284 leading to a passage 286 leading to 88. Thus, the open channel 280 and housing surface 282 are in pressure communication with the input or supply pressure side of the system, and the open channel 284 of surface 282 is with the variable output pressure side of the meter.

FIG. 19 shows a rear view of the module base 206. That is, the module base is viewed from the direction of the reference arrow 290 in FIG. 14, and the electrical compartment 256 has been removed to facilitate drawing the back surface 292 of the module base 206. FIG. 19 shows the module base 206,
The housing 2 is used to fluidly connect the parts of the instrument to each other.
02 shows several fluid passages and several passages provided in communication with the channels. For example, in FIG. 19, passage 29
Reference numeral 4 is a relay exhaust passage, passage 296 conveys the supply pressure to the relay, passage 298 conveys the fluctuating pressure of the relay and is therefore provided with a meter output. Passageway 300 communicates with output pressure gauge 264 and passageway 302 communicates with input pressure gauge 266.

Passage 304 couples to output pressure sensor 354 and passage 306 connects to the I / P converter supply pressure input (see FIG. 16).

As can be seen from the position of the parts shown in the exploded views of FIGS. 13 and 14, and with reference to FIGS. 18 and 19, the input supply pressure of the input port 276 connected to the passage 278 and channel 280 is Communicate with 296 to provide pressure to relay 262. The relay exhaust passage 294 passing through the passage 318 (see FIG. 18) exhausts from the relay exhaust port 308 shown in FIG. The plastic vent 309 prevents dust from reaching the relay exhaust port 308.

A gasket 310 formed of a flexible rubber material is provided between the surface 282 of the housing 202 and the surface 292 of the module base 206. Gasket 310 covers open channels 280 and 284 to form fluid passages within housing 202. In addition, the gasket 310 includes a group of apertures that connect the fluid channels between the module base and the housing as desired. For example, module base 2
06 passages 294, 296, 298 and respective passages 318,
Note the apertures 312, 314, 316 aligned with the channels 280, 284, respectively.

The removable cover 208 includes transparent portions 320, 322 so that the pressure gauges 264, 266 can be seen when the cover is closed in the normal position. As can be seen in FIG. 14, the cover 208 includes a pair of curved ears 3.
24 are provided. The cover 208 includes the tip 32 of each ear 324.
6 is attached to the module base 206 by first lifting the cover 208 until it directly faces each cover attachment slot 328 of the module base top wall 330. As a result, the curved ear portion 324 is
Almost aligned with the vertical slots, so the front edge 33 of the cover
2 until it hits the upper wall 330 of the module base,
Can be inserted into the slot. At this point, the cover 208 can rotate downwards to the closed position with the curved ear 324. The ears help hold the cover in the lower closed position.

Referring to FIGS. 15-18, the details of mounting the pressure components on the module base 206 and connecting the fluid interconnects to the appropriate passages are illustrated. For convenience, in FIG. 15, the input pressure side is set to “IN” and the output pressure side is set to “O”.
16, the supply pressure through passage 306 is due to the input port 276 (see FIGS. 18 and 19), channel 280, hole 309 in gasket 310.
(See FIG. 13) through the passage 306.
The passage 306 interconnects with a cross passage 336 that communicates with the passage 272 that supplies the input supply pressure to the I / P converter 260.

The pressure output side of the I / P converter 260 is connected to the passage 274 and then to the vertical passage 338 of the dividing wall 258, which is connected to the input diaphragm of the pressure relay 262 as shown in FIG. Is connected to the fluctuating pressure input to. The pressure gauge 266 is attached to an upright ledge 340 (see FIG. 19) containing a passage 342 that communicates with the passage 302 and allows the input supply pressure from the channel 280 and the input port 276 to pass through the pressure gauge 266.

Referring again to FIG. 17, it can be seen that the output pressure gauge 264 is similarly attached to the upright ledge 344. The ledge 344 then includes a passage 346 that communicates with the passage 300, which passes through the hole 315 in the gasket 310 and into the channel 284 of the housing 202.
I have contacted. Therefore, the gauge 264 can sense and display the output pressure of the meter.

The meter fluctuating output pressure caused by the pressure relay 262 couples from the output chamber of the pressure relay 262 into the passage 348 and through the fire arrester 350 to the cross passage 3
04, 304 is a hole 313 in the gasket 310.
The pressure passing through is transmitted to the channel 284 of the housing 202. As shown in FIG. 16, a pressure sensor 354 can be provided to sense the output pressure through the passage 348. When this instrument is used as a valve positioner, pressure sensor 354 can be used for diagnostics. Using this instrument as a current pressure transducer, the pressure sensor 354 acts as a feedback mechanism for the system. The details will be described below.

Referring now to FIG. 20, there is a schematic block diagram of a meter 200, the major components of which are shown in a functional block diagram for either the valve positioner or the pressure transducer. Module base 206, as illustrated for the preferred embodiment of the invention shown in FIGS.
7 shows a current pressure positioner in the form of a valve positioner with an I / P converter 260 and a pressure relay 262 attached to the. The housing 202 also includes a housing portion, that is, the electrometer 21 including the position electrometer 224.
Integrated hollow boss 214 for storing 6 and internal pocket 220
Built in. When used as a valve positioner, the instrument 200 has a shaft 232 with a feedback arm 356.
Feedback arm 356 (see FIG. 1).
Feedback arm 3 with screw mounting means 358 for mounting the positioning device shaft 232.
It is equipped with 56.

Referring to FIG. 20, a fluid control valve 360 and a sliding valve stem actuator 362 are schematically depicted.
The valve actuator incorporates a pin 364 connected to move with the valve during linear movement of the valve stem. Therefore, the valve rod 3
When 62 moves up and down as shown by the reference arrow in FIG. 20, the pin 364 also moves with the valve stem, and the pin is connected to the feedback arm 356, so that the feedback arm is the reference arrow in the direction of rotation. Rotate as shown. Rotation of the feedback arm 356 causes the electrometer shaft 232 to rotate, changing the position of the electrometer 224 and the changed position sensed by the position sensor 366, coupling the fluctuating current to the input of the I / P converter 260. . Other feedback elements can be used, including capacitors, inductors, active elements, rather than electrometers.

FIG. 12 shows pin 364 supported in the biased position of slot 368 of feedback arm 356.
Is illustrated. Spring clip 370 is biased to retain pin 364 to the side of slot 368. Thus, when the pin 364 moves in a motion that follows the valve stem 362, the pin 364 also moves linearly within the slot 368,
The feedback arm 356 is rotated to change the change in valve position into a change in the position of the electrometer 224.

A signal indicating a change in the position of the electrometer is transmitted by the electrometer lead wire 226 to a position sensor 366 mounted on the main circuit board 230 in the electrical compartment 256. The corresponding variable current signal input to the I / P converter 260 is at the input lead 268 from the circuit board 230.
It passes through the aperture 270 and is sent to the I / P converter 260.

Therefore, the instrument is a valve positioning device 200.
In the preferred embodiment of the invention illustrated, which acts as a variable pressure output at output port 298, the valve stem 362 and pin 36
Move 4 in a certain way. This movement is converted by the feedback arm 356 to the changing position of the electrometer 224. The changed position is sensed by the position sensor 366 and transformed into a fluctuating current and I / O on the lead 268.
It is supplied to the P converter 260, and the fluctuating pressure is supplied to the pipe line 274. According to a significant advantage of the present invention, the meter can easily be retrofitted into a pressure transducer. This refurbishment may require the electrical compartment 256 to be replaced to provide a new main circuit board 230. That is, it is preferable that the circuit board 230 and the electric components inside the electric section 256 are packed in a hollow structure. However, the electrical compartment can be used as a pressure transducer by removing the four screws 372 to separate the module base 206 from the housing 202 and the plugs 248 and 228 from the main circuit board 230 before removing the electrical compartment 256. It can be easily changed by replacing it with a suitable one. Also, the electrometer 16 and bushing 212 can be removed from the housing boss 214 and replaced with a suitable plug, or these components can be left in place and disconnected from the main circuit board. In any case, in the current pressure transducer mode, the feedback of fluctuating pressure at output port 288 is coupled through pressure sensor 354 and input lead 268.
To provide the fluctuating current signal supplied to the I / P converter 260 at.

If the original instrument was assembled as a current-pressure transducer, retrofitting the instrument into a current-pressure positioner would place the electrometer 216 and bushing 212 in the inner pocket 220 of the housing boss 214 and move the main circuit. Foundation 23
0, and preferably the entire electrical compartment 256, is replaced with one adapted for the operation of the valve positioner, the feedback arm 356 is attached to the electrometer shaft 232 and the pin 364 is placed in the slot 368 for sliding valve stem operation. It is understandable that this is the case. If a rotary shaft actuator were used for the fluid valve instead of a slide valve stem, a suitable feedback arm, such as feedback arm 356, could be coupled to the electrometer shaft 232 to provide a suitable rotary motion feedback link from the rotary actuator. Also linked to the movement of the feedback link, the electrometer axis 23
It is, of course, understood that two rotations are produced. Instead of an electrometer, other types of feedback elements can be utilized and incorporated into the meter 200 according to the teachings. For example, a feedback element using a capacitor, an inductor, and an active element can be used instead of the electrometer or in combination.

The feedback arm 356 is preferably stabilized with respect to the housing during transit and during initial calibration, for example as shown in FIG. 11, using a pin 374 that passes through the appropriate aperture of the feedback arm 356. During operation of the instrument 200, the pin 374
Remove.

Referring now to FIGS. 12 and 14, clamping the diaphragm to eliminate the need for machine screws,
Figure 3 shows an improved pressure relay utilizing plastic molded structural parts that can be ultrasonically welded to provide a pressure seal. According to this aspect of the invention, the pressure relay assembly cost is drastically reduced and the slack is minimized. In particular, the plastic body part is made of glass-filled polyphenylene oxide. The diaphragm is formed of polyester fiber and nitrile. The O-ring is made of Buna N rubber material. In particular, input diaphragm 380, supply bias diaphragm 382, feedback diaphragm 38.
4 is a relay body part and is spatially separated and held,
It forms the necessary chamber in the relay. The exhaust main body 386, the diaphragm holder 388, the diaphragm spacer 390, and the supply main body 392 are plastic parts that separately hold the diaphragm and form each relay chamber. Each relay chamber, such as that formed in relay 262, is shown in FIG. 12 as an input pressure chamber in communication with passageway 338, exhaust chamber 394, supply pressure chamber 396, output pressure chamber 398.

All of the above relay components can be ultrasonically welded using conventional ultrasonic welding equipment and techniques. Thus, the main relay body parts are easily assembled by ultrasonic welding and do not require metal screws or metal accessories.

The remaining metal parts, such as the valve plug 400, conventional supply port, exhaust port, etc., can then be inserted into the relay. The metal cap 402 and the bereville spring 404,
It is used with appropriate screws 406 to secure the relay 262 to the module base 206. Relay the O-ring 26
Used around the two, various relay chambers are sealed from each other when attached to the module base 206.
Further, since the supply pressure from the chamber 396 is supplied to the formed chamber 410 by the relay 262,
Chamber 41 between cap 402 and supply body 392
0 is maintained at the supply pressure. Thus, this improved pneumatic relay also includes the substantially constant supply bias pressure improvement described above in connection with the embodiment of FIGS.

The detailed description so far has been given only for the convenience of understanding, and modifications will be obvious to those skilled in the art, so that no unnecessary limitation is made.

[Brief description of drawings]

FIG. 1 is a front view depicting an electric current pressure transducer having an enclosure with a housing and a removable module base in accordance with the present invention.

FIG. 2 is a cross-sectional view of the current-pressure converter shown in FIG. 1 taken along the line 2-2.

3 is a sectional view of the current-pressure converter shown in FIG. 1 taken along the section line 3-3 of the module.

FIG. 4 is a cross-sectional view of the current-pressure converter shown in FIG. 2, taken along section line 4-4.

5 is a sectional line 4A-4 of the current-pressure converter shown in FIG.
It is the fragmentary sectional view cut along A.

6 is a partial cross-sectional view of the current-pressure converter shown in FIG. 1 taken along the line 5-5.

FIG. 7 is a front view showing an interconnection board for connecting electrical terminals.

FIG. 8 is a front view showing the interior of a housing with an interconnect base mounted in a floating manner.

FIG. 9 is a cross-sectional schematic view of shoulder screws for floatingly mounting an interconnection board.

FIG. 10 is a supply bias pneumatic relay.

FIG. 11 is a perspective view of the preferred embodiment of the invention, illustrating a modular valve positioner that can be easily retrofitted into a pressure transducer.

12 is a sectional line 11 of the valve positioning device shown in FIG.
FIG. 12 is a sectional view of the preferred embodiment of the invention according to -11.

13 is an exploded perspective view of the modular valve positioning device of FIG. 11. FIG.

14 is an exploded perspective view of the modular valve positioning device of FIG. 11. FIG.

FIG. 15 is a front view of a module base excluding some components. There is.

16 is a sectional line 1 of the module base shown in FIG.
It is sectional drawing which followed 4-14.

FIG. 17 is a partial cross-sectional view showing a pressure sensor that senses output pressure.

FIG. 18 is a front view of the instrument housing showing channels on the surface of the fluid passages.

19 is a front view of the module base showing the module base surface facing the housing of FIG. 18. FIG.

FIG. 20 is a schematic block diagram illustrating an electropneumatic converter that can be easily converted from a valve positioner to a pressure converter and vice versa.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Stephen Burr Paulus USA 50158 Iowa Mar Shalltown Edgebrook Drive 2007 (72) Inventor Stanley Ronald Good USA 50158 Iowa Mar Shalltown Richard Rain 511 (72) Inventor Barry Lynn Gadder United States 50158 Iowa Martial Town Picker Ring Dial. 2745 Di

Claims (21)

[Claims] 1. A feedback element output for an electro-pneumatic conversion instrument, wherein a feedback element with a shaft connectable to a valve stem can be used to easily retrofit a pressure transducer to a valve positioner for indicating valve position. , Which corresponds to the valve stem position, wherein the instrument comprises a housing defining a hollow interior, and an enclosure comprising a module base with removably insertable electropneumatic components in the housing; Includes a housing portion adapted to house and mount the feedback element and shaft when retrofitting an instrument to a valve positioner, the housing portion communicating with the hollow interior to provide the feedback element output, The module base through the housing part and the hollow interior. It can be connected to the electrical component. 2. An electro-pneumatic conversion instrument according to claim 1, wherein the housing is open at one end directly into the hollow interior of the housing. 3. The electro-pneumatic conversion instrument according to claim 1, wherein the housing portion includes an extended cylindrical boss extending along the housing. 4. The electro-pneumatic conversion instrument according to claim 3, wherein the extended cylindrical boss is formed integrally with the housing. 5. The electro-pneumatic conversion instrument according to claim 4, wherein the extended cylindrical boss comprises a pocket interior that receives the feedback element at one end inside the pocket, one end inside the pocket having a feedback element output,
A part that intersects the hollow inside of the housing so that it can be connected to the electrical parts of the module base through the housing and the hollow inside. 6. An electropneumatic conversion instrument according to claim 5, comprising a bushing that can be threadably mounted on the extension cylindrical boss at the other end of the hollow interior to support the feedback element shaft. 7. An electropneumatic conversion instrument according to claim 6, wherein the feedback element comprises an electrometer. 8. An electropneumatic converter instrument according to claim 1, comprising an electrical terminal box, means for replaceably mounting said electrical terminal box on said housing, and a passageway through said electrical terminal box, said housing comprising: The electrical connection between the terminal box and the electrical components of the module base is made possible through the passage means and the hollow interior of the housing. 9. The electro-pneumatic conversion instrument according to claim 8, wherein an electric terminal board is replaceably attached to the terminal box,
A terminal cover provided with a removable cover. 10. The electro-pneumatic conversion instrument according to claim 9, comprising a cable mounting band connected to the electrical terminal board and extending through the passage means and the hollow interior of the housing to connect to the electrical components of the module base. The terminal board and the cable attachment band are unit devices that can be exchanged to receive corresponding desired functions such as analog, digital, and communication data protocols. 11. The electro-pneumatic conversion instrument according to claim 10, wherein the cable mounting band includes a radio frequency interference filter in the unit device. 12. The electro-pneumatic conversion instrument according to claim 1, wherein the screw means for attaching the module base to the housing with a screw and the electrical and pneumatic components of the enclosure enclose when closed. And a removable cover that can be removed for easy access to the pneumatic components. 13. The electro-pneumatic conversion instrument according to claim 12, wherein the cover and the module base are detachably mountable without any other mounting structure, and a built-in means combined with the module base and the removable cover is provided. What to prepare. 14. The electro-pneumatic conversion instrument according to claim 13, wherein the built-in means comprises at least one slot in the module base and at least one protruding curved portion in the cover, When the cover is attached to the module base, the cover can be inserted into the slot, and the curved portion can rotate the cover to a closed position while holding the cover on the module base. 15. The electro-pneumatic conversion instrument according to claim 14, wherein said built-in means comprises a pair of said slots on both sides of said module base, and said projecting curved portions coupled to each of said slots. 16. The electro-pneumatic conversion instrument according to claim 1, further comprising a pneumatic relay attached to the module base, wherein the plastic relay body part and the rubber diaphragm, and the plastic relay body part and the rubber diaphragm are provided. Those equipped with ultrasonic welding means for welding. 17. A housing comprising a housing defining a hollow interior terminating in a housing mounting surface, the housing comprising an enclosure having an inlet pressure port and an outlet pressure port, and respective channels communicating with the input port and the outlet port, respectively. A housing mounting surface, a module base that is removably insertable into the housing hollow interior, is placed face-to-face, and has an electropneumatic component attached to the housing surface that includes a module base mounting surface, and The module base mounting surface comprising a communicating module base fluid passageway; and an aperture covering the channel to define a housing fluid passageway and connecting the housing fluid passageway to the module base fluid passageway. When, in the middle of the module base mounting surface, air converter electrostatic consisting gasket that is in close proximity to them. 18. A supply bias pneumatic relay for fluid control, comprising: a supply pressure inlet, a fluctuating pressure control inlet, an actuator pressure outlet, a housing with an exhaust outlet, the supply pressure inlet comprising: Supply port connected to the device pressure outlet, the supply pressure inlet, an exhaust port connected to the exhaust outlet, an input diaphragm connected to the fluctuating pressure control inlet,
Valve plugs that bite into contact with the supply port and the exhaust port and connect to the input diaphragm to apply a fluctuating pressure to the actuator pressure outlet in response to fluctuating pressure at the fluctuating pressure control inlet. Supply bias diaphragm means comprising a pair of diaphragms mounted in the middle of each valve plug and the input diaphragm, the pair of diaphragms defining a supply bias cavity, supply of the supply pressure inlet to the actuator pressure outlet Flow means connecting the supply pressure inlet to the supply bias cavity to bias the relay to create an initial pressure at the actuator pressure outlet that corresponds to a pressure-based pressure fluctuation at the variable pressure control inlet. 19. A supply bias pneumatic relay according to claim 18, wherein said flow means is limited between said supply bias cavity and said supply pressure inlet for isolating the bias cavity from transient fluctuations in supply pressure. Equipped with a corridor. 20. A supply bias pneumatic relay according to claim 19, wherein said flow means comprises a capillary aperture. 21. A supply bias pneumatic relay according to claim 20, wherein said pair of diaphragm means have different diaphragm areas.